SILAR-deposited manganese doped zinc oxide thin films for NO2 gas detection applications

The structural, optical and gas detection characteristics of Mn-doped ZnO thin films synthesised by the Successive Ionic Layer Adsorption and Reaction (SILAR) process with varied doping concentrations (4, 6 and 8%) were examined. X-ray diffraction data was used to investigate the structural properties and confirm the hexagonal wurtzite crystal structure. The surface morphology and the existence of all elements were verified using a field emission scanning electron microscope and energy dispersive X-ray spectroscopy, respectively. To explore the vibrational bands present in Mn-doped ZnO films, we used FTIR spectra at ambient temperature. Ultraviolet-visible analysis reveals the absorption edge, which is found in the ultraviolet area, with a minor shift towards high wave length, whereas the energy bandgap decreases as Mn concentrations increase. At 200°C operating temperature, the gas sensing properties of Zn0.92Mn0.08O showed good sensitivity, selectivity and shorter response time when compared to other prepared films.